Browser.cache.memory.capacity [upd]

: Search for browser.cache.memory.capacity . If it doesn't exist, right-click (or click the "+" button), choose New > Integer , and name it exactly as above.

When modifying browser.cache.memory.capacity , users often interact with a related setting: browser.cache.memory.enable . Browser.cache.memory.capacity

On older systems with very limited RAM (e.g., 2GB or less), Firefox’s automatic cache might still be too aggressive. By setting a fixed, lower value (e.g., 32768 = 32 MB), you can force Firefox to use less RAM for caching. The trade-off is potentially slower back/forward navigation. : Search for browser

To fully master Firefox's cache behavior, you should also be aware of these sibling preferences: right-click (or click the "+" button)

Yes. Memory cache and disk cache ( browser.cache.disk.capacity ) are separate.